Nietzsche's philosophy engaged with a wide range of ideas related to the human condition, including morality, language, value, aesthetics, culture, and consciousness, and his body of writing spanned theoretical polemics, poetry, cultural criticism, aphorism, and fiction while displaying a fondness for metaphor and irony. Among the chief tenants of his philosophy was his radical questioning of the existence and value of objective truth. Equally central to his concerns was his atheistic critique of religion and morality, which he regarded as symptoms of historical processes erroneously taken for first causes, and of Christianity in particular, which he characterized as propagating a slave morality in the service of cultural decline and the denial of life.